ex 10 :
a)230
231
232
233
234
235
236
237
238
239
b)2010,2011,2012.......2019
2110,2111.....2119
2210,2211,2212,,,2219
2310,2311,2312,....2319
2410,2411,2412,....2419
2510,2511,.....2519
2610,2611,,....2619
2710,2711.....2719
2810,2811....2819
2910,2911,.....2919
c)4002,4012,....4092
4102,4112....4192
4202,4212,4222...4239
si tot asa